1. Field of the Invention
The present invention relates to a vapor deposition apparatus, and more particularly to a vapor deposition apparatus in which a thin film having strong adhesiveness to a substrate is formed and which is particularly applicable to a substrate material having poor thermal resistance, such as organic plastics.
2. Description of the Related Art
Conventionally, as a typical PVD (physical vapor deposition) process forming a thin film, a so-called ion plating process is known to the art, which includes generating a high-frequency electromagnetic field between the vapor exit means and an object to be vapor-deposited (substrate) to ionize the evaporated material in an active or inert gas to perform vacuum vapor deposition. Also, a DC ion plating process which applies a direct current voltage between a vapor exit means and a substrate is proposed in Japanese Patent Publications No. 29971/1977 and 29091/1977, etc. According to these methods, the substrate surface is cleaned and activated by ion impact and the adhesion of the resulted film is high. However, these methods have the drawback that, in order to attain required level of ionization, a substantial quantity of active or inert gas must be present in a vacuum chamber, so that the quality of the resulting film is not very good.
In contrast with the above methods, a CVD (chemical vapor deposition) process, wherein a chemical reaction takes place, gives a filmwise deposit using a rather simple installation as compared to the PVD process. However, the substrate must be heated to a rather high temperature, so that this method cannot be applied to a substrate having poor thermal resistance, such as organic plastics.